The present invention relates to a bearing apparatus such as a vehicle hub unit in which a rolling bearing is mounted to a shaft body.
A rolling bearing is mounted to an outer periphery of a shaft body of a hub wheel of a vehicle. A shaft end of the shaft body is bulged and deformed radially outward by rolling caulking, i.e., swaging, to be a caulked portion. This caulked portion is caulked to an outer end face of an inner ring of the bearing to thereby apply a pre-load to the bearing and to fix the bearing to the shaft body.
The shaft body of the hub wheel has a hollow structure such that a drive shaft can be inserted into the shaft body. For spline fitting with the drive shaft, an inner periphery of the shaft body has spline portions.
The spline portions are formed to be substantially adjacent to the caulked portion of the shaft end and to be formed long in an axial direction so as to mechanically connect the inner periphery of the shaft body and the drive shaft with necessary strength.
During installation of the bearing, the spline portions are liable to be deformed radially inward to such a degree as to obstruct insertion of the drive shaft into the shaft body by force applied radially outward to the shaft end during swaging the caulked portion.